Traction mechanism for tractors



Oct; 28. 1924.

S. K. WELLMAN TRACTION MECHANISM FOR TRACTORS -Filed March 18. 1921 2 Sheets-Sheet l INVENTOR J K. 71M.

Oct. 28. 1924. 1,513,144

S. K. WELLMAN TRACTION MECHANISM FOR TRACTORS Filed March 18, 1921 2 Sheets-Sheet 2 INVENTOR Patented Oct. 28, 1924.

UNITED STATES SAMUEL K. WELLIAN, OF CLEVELAND, OHIO.

TRAOTION MEQHANIBK FOR TRACTOR/B.

Application filed larch 18, 1821. Serial H0. 453,278.

To all whom it may concern:

Be it known that I, SAMUEL K. WELIMAN, a citizen of the United States, and resident of Cleveland, in the county of Cuyahoga and State of Ohio, have invented certam new and useful Improvements in a Traction Mechanism for Tractors, of which the following is a specification, reference being had therein to the accompanying drawings.

The invention relates to the traction mechanism of tractors of the crawler or, endless belt type, and is concerned especially with the form and construction of the endless belt and the cooperating driving and supporting wheels interposed between the belt and the main frame of the machine. As is well understood, the endless traction belts of a machine of this class must be adapted to suitably cooperate with driving sprocket wheels and also must function as supporting and guiding tracks for the weight-bearing wheels of the machine.

One of the objects of the invention is to provide an improved endless belt and sprocket mechanism characterized by a minimum of wear at the mutually engaging surfaces of the belt and sprockets.

Another object of the invention is to rovide an improved traction belt whic is adapted to present to a hard smooth road, supporting surfaces of adequate area to obviate penetration and injury of such road and w ich, at the same time, is also ada ted to present to a soft road gri ping su aces that give the belt an excee ngly efiective grouser action.

A further object of the invention is to provide a traction belt of the character last referred to having links that are simple in construction and adapted to be easily roduced, as by stamping or pressing or ro ing from sheet metal or by forging.

Another object of the invention is to provide a traction belt of the character referred to which has both adequate strength and light weight.

Another object of the invention is to produce a traction belt of the character referred to which can be produced at low cost.

A further object of the invention is to provide a simple, strong and light, sprocket wheel adapted to cooperate with my improved traction belt.

The nature of the foregoing objects and the manner in which they are attained will be clearly understood from the following description in connection with the accomanying drawings which illustrate referred orms of construction embodying t e invention.

In the drawings, Figure 1 is a side elevation of a tractor fitted with my improved mechanism.

Fig. 2 is an enlarged fragmentary section on the line 2-2, Fig. 1.

Fig. 3 is an enlarged fragmentary section on the line 3-3, Fig. 1.

Fig. 4 is an enlarged fragmentary section on the line 4.-4, Fig. 1.

Fig. 5 is an enlarged fragmentary plan view of a development of one of the sprocket rims of the sprocket wheel.

Fig. 6 is an enlarged fragmentary side view of the same.

Fig. 7 is a section on the line 7-7, Fig. 6.

Fig. 8 is an enlarged fragmentary view of one of the sprocket rims blanked out from plate metal and ready to be bent and pressed into shape.

Fig. 9 is an enlarged fragmentary side view of the driving sprocket wheel and belt.

Fig. 10 is a similar view of a part of the sprocket wheel.

Fig. 11 is an enlarged plan view of two of the links of the endless belt.

Fi 12 is a sectional elevation of,one of said links, the section being taken on the line 1e42, Fig.,11.

Fig. 13 is a side elevation of the links shown in Fig. 11.

Fig. 14 is a plan view of one of the links blanked out from plate metal and ready to be bent and pressed into the form shown in Figs. 11, 12 and 13.

Fig. 15 is a section through a link of modified construction.

Referring in detail to the construction illustrated, 1 designates the main frame structure of an endless belt tractor, 2 is one of the two driving sprocket wheels suitably mounted on said main frame, 3 is one of the two idlers also mounted on the main frame, 4, 4 and 5, 5 I are weight support wheels rotatably mounted on trucks 6 an 7, respectively, which are connected to the main frame by means of bars 8 and 9 and springs 10, 10, said springs being'pivotally mounted at 11 on the main frame structure. 12 designates inits entirety an endless belt track which passes around the sprocket wheel 2, and the idler 3 and upon which the weight supporting wheels 4 and 5 run.

The main frame carries the engine, transmission mechanism, control devices, drivers seat and various other parts of a tractor of this character, but the present invention is not concerned with these parts and, as they may be of any suitable construction, they need not be described.

The ground-engaging belt 12 is of a pcculiar and novel form, being made up of a series of articulated links 13. Considering one of these links as it rests upon the ground. it has a flat longitudinally extending central part 14, and side parts formed with elevations 15 which rise above the central part l-t and are recessed on their under sides, as shown in Figs. 12 and 13. These elevations 15 are preferably given a rounded or spherical form. The side parts of each link are provided at one end with pairs of apertured lugs 16, 16 and at the other end with apertured lugs 17 which are adapted to be brought into alignment with the lugs 16 of an adjacent link to receive pivot pins 18, 18. These pivot pins 18 are secured against endwise displacement by clips 19 which are preferably formed integral with the link and bent over the ends of the pivot pins 18 after the latter are inserted.

From the foregoing, it will readily be seen that the links can be formed from plate metal and in Fig. 14 I have shown a link after it has been blanked out from a. metal plate and before it has been bent and pressed into its final form. It will be observed that the tongue which is to form the outside one of each pair of pivot lugs 16 is formed with a lateral extension which constitutes the clip 19 above referred to. The blank shown in Fig. 14 is placed in a press which strikes up the elevations 15 and thereafter the extending tongues are bent to form pivot lugs 16 and 17. The bent over ends of these lugs 16 and 17 can be secured to the body of the link in any suitable manner, asby spot welding or riveting.

Instead of first forming the blanks, as shown in Fig. 14, from plate metal and then shaping them in a press, a more or less elongated strip of plate metal' can be passed through rolls to form the elevations 15 for a series of links, the latter being then separated from each other by a stamping or punching operation.

Again, instead of forming the links from piste metal as above described, they may formed by forging suitable blanks to the form shown in i 15. In this latter case,

it is necessary to rill out the pin apertures of the pivot lugs. The forging method has the advantage that different parts of the link can be made of different thicknesses, as

. desired, to insure both adequate strength and minimum weight. g

While I have, in each of the constructions shown, rovided pins for pivotally connecting the inks together, the links can be connected in other ways.

On reference to Figs. 1 and 2, it will be seen that the weight-supporting wheels 4 and 5 are of a size and form to run between the elevations 15 of the links and upon the flat central parts 14 thereof, the Hat parts of the link affording a smooth track while the elevated sides of the link serve as guides to hold the wheels on the truck.

The driving, sprocket wheel 2 can be constructed in various ways to cooperate with the links of the belt 12, but I prefer to construct the sprocket wheel as shown in the drawings. As shown, said wheel comprises a pair of discs 20, 21 which are pro vided with suitable hub arts and their outer peripheries are boltet to an intermediate member having a radially extending flange 22. To this flange 22 are riveted a pair of sprocket rims 23, 23. Each of these rims is formed with a series of inwardly turned flanges 24, 24 which abut against the flange :22 and are perforated to receive rivets 25 which secure the rims to said flange. Each rim is formd with a series of alternating depressions 26. 26 and elevations 27, 27, said depressions being adapted to receive the elevations 15 of the belt links so that the elc rations 27 of the wheel serve as sprockets. It is to be observed, however, that the coaction of the sprocket elevations 27 and the link elevations 15 difi'ers radically from that which characterizes the ordinar sprocket and chain. That is to say, in the present construction. the elevations 15 of the links are intermediate the pivotal joints of the links, in fact approximately in the longitudinal centers ,of the links, whereas in the commonly employed prior sprocket and chain constructions, the chain. parts on gaged by the sprockets are disposed at and usually concentric with the pivotal joints. The result is that the rubbing and wear between the eoacting sprocket and chain surfaces which characterize the usual prior con structions,.are largely obviated in my construction.

'Hie rim or sprocket part of the drive wheel 2 can be made in any suitable way. but I prefer the construction illustrated in which the sprocket rims 23 are formed from sheet or plate metal. In Fig. 8, I have shown a part of one of the rims blanked out from plate metal and ready to be bent and pressed into finished form. The wheel 3, being an idler, is shaped at its periphery like the wheels 4 and 5, as shown in Fig. 2.

On referring to the various figures of the drawin it will be seen that a traction belt made with my improved form of link is well adapted to cooperate with the drive sprocket and with the weight-supporting wheels of the machine. As above pointed out, the flat central parts of the links constitute a smooth, substantially continuous track for. the supporting wheels and said wheels are effectivel guided to follow this track by the elevate side sections 15 of the links. The securing of a continuous smooth track for the supporting wheels is tacilitated b arranging the pivot connections of the lin between the side parts thereof so that the flat central parts 14 of the links can be brought relatively close together. The connecting 'oints are preferably arranged with their pivotal axes approximately in the planes of the flat central parts of the links.

In addition, my improved traction belt is admirably ada ted to travel over all sorts of surfaces. 6n a hard, smooth road, the

hat central parts of the links'constitute a smooth tread of ample area so that'thc surface of the road is not injured. On the other hand, when the tractor is traveling over soft ground, the belt links sink into the ground and the elevated side parts of the links, recessed on their under sides, grip the ground with an effective grouser action.

While the links of m improved belt are very li ht in weight, t ey are, because of their orm, extremely rigid and strong. Also, with suitable equipment, the links can It will be understood that various modifications of the form and arrangements of the parts of my improved traction mechanism can be made without sacrificing theadvantages of the invention, the scope of which is indicated by the appended claims.

What I claim is; a

1. In a traction mechanism for. tractors, the combination with an endless ground-engaging belt having articulated of which each has a flat longitudinally extending central part andv elevated aide parts which are recessed on their under: sides to afford a grouser action, of a driving sprocket wheel having engagement with the belt links onlythrou the wheel a rockets and said elevated 'si e parts of the It links.

2. In a traction mechanism for tractors, the combination with an endless ground-engagi belt having articulated links of which each has a flat longitudinally extending. central part and elevated side arts which are recessed on their under si es to afford a grouser action, of a driving wheel having a rockets formed tooperatively ene saig elevated side parts of the belt inks and havin no other'engagement with said links, an wei ht-sustaining wheels adapted to roll upon t e central parts of the links between the elevated side parts thereof and be guided by said side parts.

3. In a traction mechanismio'r tractors, the combination with a driving sprocket wheel and weight-supporting wheels, of an endless ground-engaging belt comprising a ing wheel having sprockets formed to series of links formed to engage the driving wheel sprockets, each link having a flat'longitudinally extending central part and elevated side parts which are recessed on their under sides to afiord a .grouser action, and means pivotally connecting the links on axes approximatel in the planes of the flat central parts oft e links, whereb a continuous surface is afforded on whic the weightsupporting wheels roll.

.4. Ina traction mechanism for tractors,

the combination with an endless ground-enga ing belt comprising a series of links of whicheach has a flat longitudinally extendinglacentral part and eevated side parts which are recessed on their under sides to afford a grouser action and means pivotally connecting the side parts of adjacent links gaging belt comprising a series of metal be made in quantity at a very moderate cost. 1 f

'nectzngtogether ad acent links on axes aps" and metallic means for pivotally conproximately in the planes of the radially outermost ground-engaging ortions of the links, said links being forme with elevated parts disposed substantially midway between their pivotal connections, of a drivo eratively engage said elevated parts of tlib belt links to eflect either forward or backward traction substantially without lost Ignition between the driving wheel and the e t. a

6. In a traction mechanism for tractors, the combination with an endless groundengaging belt comprising a series of metal links each having a flat longitudinally extending central part and elevated side parts which are recessed on their under sides to afford a grouser action and metallic means for pivotally connecting together adjacent links on axes approximately in the lanes of said fiat central parts of the lin s, of a driving wheel having sprockets formed to operatively engage said elevated parts of the belt links to efi'ect either forward and backward traction substantially without lost motion between the driving wheel and the belt.

7. A sprocket wheel for tractors and the like comprising in combination a body and a pair of circumferentially extending late metal sprocket rims, each of said rims aving a series of inwardly bent flanges rigilly secured to the peripheral part of the dy and being formed with depressions adapted to o ratively engage elevations on a traction lt.

8. In a traction mechanism for tractors,

the combination with an endless ground-en gaging belt comprising a series of links ivotally connected to ether, said links each liaving a flat longitu inally extending central part -and elevated concavo-convex side parts with their concave sides underneath to afford a grouser action, of a driving sprocket wheel having sprockets formed to operatively en go the up r convex surfaces of said si e parts of e links.

9. A traction belt for tractors comprising a series of articulated links each formed of plate metal and having a flat central part extending longitudinally from the front cdge'to the rear edge of the link and elevated side parts with recesseson their under sides to afiord a grouser action, and means ivotally connecting the links on axes approximately in the planes of the flat central parts of the links.

10. A traction belt for tractors compris ing a series of links each of substantially uniform thickness and having a flat lon 1- tudinally extending central part and e evated side parts w1th recesses ontheir under sides to afi'ord a ouser action, and means pivotally connecting the links on axes approximately in the planes of the flat central parts of the links.

11. A traction belt for tractors comprising a series of links each formed of plate metal. and having a flat longitudinally extending central part and elevated side parts with recesses on their under sides to afford a grouser action, and means pivotally connecting the links on axes approximately in the planes of the fiat central parts of the links.

12. As an article of manufacture, a traction belt link for tractors having a flat longitudinally extending central part, elevated side parts which are recessed on their under sides to afford a grouser action, and means at its front and rear edges adapted to cooperate with the rear and front edges, respectively, of similar links to form piv otal joints with axes approximately in the planes of the said central part.

14. As an article of manufacture, a traction belt link for tractors formed of plate metal and having a flat longitudinally extending central part, elevated side parts with recesses on their under sides to afiord a grouser action. and means at the front and rear edges of said side parts ada ted to cooperate with the rear and front gas.

respectively, of similar links to form pivotal joints with axes a proximately in the plane of the said centra part.

In testimony whereof, I hereunto afiix my signature.

SAMUEL K. WELLMAN.

Certificate of Correction.

It is hereb certified that in Letters Patent No. 1,513,144 granted October 28 1924, upon e applicutipn of Samuel K. of Cleveland, Ohio, for In; Improvement m Tract1on Mechanism for Tractors, an error appears in the grmted speclficatlon reqmring correction as follows: Page 4, line 52, last claim. or thepumex al 14 read 18; and that the said Letters Patent should be read mth tlns ooneetmn therein that the same my conform to the record of the m the Patent Oflice. Y

Signed and sealed this 3d day of March, A. D. 1925.

[m] KARL FENNING,

Acting C'Muioner of PM. 

